The present invention relates to a statistical ventilation control device for ventilated cigarettes.
Ventilated cigarettes normally consist of a filter-tip cigarette, the cover band of the filter of which presents ventilation holes formed by means of perforating devices, for enabling the smoker to inhale, together with the smoke produced by combustion of the tobacco, a certain amount of air for reducing both the temperature and the amount of harmful substances contained in the smoke.
During manufacture, ventilated cigarettes are normally subjected to constant hundred percent control to determine "ventilation" performance and so enable rejection of any poorly ventilated cigarettes as well as continuous adjustment of the perforating devices.
In actual practice, however, hundred percent control has proved not only relatively expensive and, in view of the limited time available, invariably unreliable, but also substantially superfluous, by virtue of any change in ventilation performance occurring in the form of "tendencies" as opposed to random, sharp variations. As such, statistical ventilation control (e.g. one out of every thirty cigarettes) has been found to be no less effective than hundred percent control, and is decidedly cheaper and more reliable by virtue of the smaller number of cigarettes involved and, hence, the additional time available for control.